In today's world, many vehicles are equipped with systems for facilitating remotely controlled vehicle functions such as passive entry and passive starting (i.e., PEPS) of a host vehicle. When a vehicle is equipped with a PEPS system, a user may carry a mobile communication unit which can communicate with a base station located in the vehicle. To initiate communication the base station may emit a relatively powerful Low Frequency (LF) electromagnetic field, causing a mobile communication unit that is sufficiently close to the base station to awaken. Once the mobile communication unit is awake, it may use Radio Frequency (RF) transmissions to dispatch signals, which may be validated by the base station. If the base station recognizes and approves the identity of the mobile communication unit, (i.e., the base station authenticates the mobile communication unit), the base station may facilitate the performance of a predefined vehicle function, such as actuating a door lock mechanism, causing the door to become unlocked. In such passive systems, the functions may be performed based solely on the position, or changes in the position, of the mobile communication unit, and the functions may be performed even though no specific command may have been initiated by the user.
For example, in some passive systems, an approach of the mobile communication unit toward the vehicle may be detected so that a desire for one or more vehicle functions to be performed (e.g., unlocking doors) may be anticipated and automatically provided in a manner that enhances the operator experience. In other passive systems, a departure of the mobile communication unit away from the vehicle may be detected so that one or more other functions (e.g., locking vehicle doors) may be performed.
In addition to the above-described passive communications, a vehicle communication system may also be configured to facilitate active communications among system components. Active communications may include transmissions initiated by a user seeking performance of a pre-defined function. For example, a user, by pressing a button or actuating a switch on a mobile communication unit, may actively initiate active communications with the vehicle, sending a command to lock or unlock the vehicle doors or to actively start the vehicle engine.
In some vehicle communication systems, the effective operational range for communications between a mobile communication unit and the vehicle may be subject to variation, depending upon a number of variable factors such as the state of battery charge and local environmental conditions. Some conventional systems may have an extended range of operation that exceeds one hundred meters. Such extended ranges of operation may be useful for enabling a user to reliably control vehicle functions in a variety of conditions without the necessity of being closely proximate the vehicle. For example, currently available systems may enable a user to remotely start their vehicle engine or to lock or unlock doors of the vehicle from a remote location such as several stories up in an office building.
In such systems, there may be no limitations on the exercise of control over vehicle functions other than an effective range of communication between the vehicle and the remote communication unit. Such extended ranges of operation are likely to facilitate control over vehicle functions beyond direct line of sight and/or outside of an audible range of the vehicle. Sometimes the user may wish to exercise control over a vehicle function, such as activating the door locks at a long distance from the vehicle and outside of a direct line of sight to the vehicle. There may be little risk of negative consequences associated with enabling some forms of control (e.g., locking the doors) as the harm associated with an inadvertently dispatched signal (unintentional locking of the doors) may be relatively low. Other functions, however, such as remotely opening a vehicle sunroof, may entail more significant negative consequences if requested inadvertently when the vehicle is out of sight of the user.
In a conventional system, a user may be required to rely on personal observation to determine the status of various attributes of the vehicle. For example, if an aperture is open and a user is within eyesight of the vehicle, the user may visually observe that it is open and realize that an attempt to lock the aperture will not be effective in securing the vehicle. Similarly, if an aperture is open and a user is within earshot of the vehicle, and if the ambient level of noise is not excessively high, and if the vehicle is so equipped, then the vehicle may emit an audible tone signalling the failure to secure the vehicle, which tone the user may hear causing the user to realize that the aperture is open and the attempt to secure it ineffective.
Unfortunately, if the user is not within line of sight of the vehicle and, for example, is located in an area of high ambient noise, the user may not receive any indication or otherwise have reason to realize that an intentionally requested action was not performed or that an inadvertently requested action was performed. For example, the user may not have been sufficiently close to the vehicle to hear the vehicle emit its error tone, or the user may not have been able to see a window opening or to hear the engine starting. Accordingly, a user may be left with no means for verifying the status of the vehicle or its functions other than by approaching the vehicle and inspecting it. This can lead to uncertainty about the status of the vehicle.
The present invention attempts to address or ameliorate at least some of the above problems associated with vehicle communication systems.